Ketoprofen and diclofenac removal and toxicity abatement in a real scale sewage treatment Plant by photo-Fenton Process with design of experiments

Abstract

The disposal of effluent and sludge containing emerging contaminants (ECs) are the main problems associated with most traditional treatment methods. Non-steroidal anti- inflammatory drugs (NSAIDs) require more complete treatments integrated with conventional processes to enable circular economy and the water-energy-food (WEF) nexus. Different options to traditional technologies have been employed in the treatment of effluents, such as advanced oxidation processes (AOPs). However, few studies use real scales integrated with existing technologies. This work evaluated the use of AOPs for the degradation of ketoprofen (KET), diclofenac (DCF), and the DCF+KET mixture in an anaerobic effluent matrix, post-treated by an Upflow Anaerobic Sludge Blanket Reactor (UASB) in a real-scale Sewage Treatment Plant (STP). A Factorial Experimental Design was proposed and after 2 h of treatment the efficiency was evaluated by the decrease in total organic carbon (TOC), decrease of drugs concentration, physicochemical and ecotoxicity parameters. As a result, the photo-Fenton process showed greater efficiency in the degradation of KET (97.2% ± 1.6), DCF (72.7% ± 4.9), and the mixture of the two drugs DCF+KET (66.0% ± 2.5), improved the quality of the effluent in the removal of COD, BOD, and turbidity, and reduced toxicity in tests performed with Artemia sp. and Lactuca sativa. The integration between AOPs and UASB as a sewage treatment technology widely used as primary and secondary treatment, allowed to optimize the sewage treatment system for an ideal arrangement. As a consequence, it possesses the capacity to eliminate conventional organic matter and efficiently degrade emerging pollutants.